Coupling apparatus, exposure apparatus, and device fabricating method

ABSTRACT

A lithographic projection apparatus includes an illumination system arranged to condition a radiation beam, a support structure configured to hold a patterning device, the patterning device being capable of imparting the radiation beam with a pattern, a substrate table configured to hold a substrate, a projection system arranged to project the patterned radiation beam onto a target portion of the substrate, and a liquid supply system configured to at least partly fill a space between the projection system and the substrate, with a liquid. The projection system includes a first part and a second part that are two separate physical parts that are substantially isolated from each other such that vibrations in the second part are substantially prevented from being transferred to the first part. Each part includes an optical element of the projection system and the first and second parts are not attached to and movable with the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Division of application Ser. No. 12/585,498 filed Sep. 16,2009, which in turn is a division of application Ser. No. 11/322,125filed Dec. 30, 2005, which in turn is a Continuation of InternationalApplication No. PCT/JP2004/010059, filed Jul. 8, 2004, which claimspriority to Japanese Patent Application Nos. 2003-272615 (filed on Jul.9, 2003) and 2003-281182 (filed on Jul. 28, 2003). The disclosures ofthe aforementioned applications are incorporated herein by reference intheir entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a coupling apparatus that couples twoobjects, an exposure apparatus that exposes a substrate via a projectionoptical system in a state wherein a liquid is filled between theprojection optical system and the substrate, and a device fabricatingmethod that uses the exposure apparatus.

2. Description of Related Art

Semiconductor devices and liquid crystal display devices are fabricatedby a so-called photolithography technique, wherein a pattern formed on amask is transferred onto a photosensitive substrate. An exposureapparatus used by this photolithographic process comprises a mask stagethat supports the mask, and a substrate stage that supports thesubstrate, and transfers the pattern of the mask onto the substrate viaa projection optical system while successively moving the mask stage andthe substrate stage. There has been demand in recent years for higherresolution projection optical systems in order to handle the much higherlevels of integration of device patterns. As the exposure wavelength tobe used is shorter, the resolution of the projection optical systembecomes higher. As the numerical aperture of the projection opticalsystem is larger, the resolution of the projection optical systembecomes higher. Consequently, the exposure wavelength used in exposureapparatuses has shortened year by year, and the numerical aperture ofprojection optical systems has also increased. Furthermore, thecurrently mainstream exposure wavelength is the 248 nm KrF excimerlaser, but an even shorter wavelength 193 nm ArF excimer laser is alsobeing commercialized. In addition, the depth of focus (DOF) is alsoimportant as well as the resolution when performing an exposure. Thefollowing equations respectively express the resolution R and the depthof focus S.

R=k ₁ ·λ/NA,  (1)

δ=±k ₂ ·λ/NA ²,  (2)

Therein, λ is the exposure wavelength, NA is the numerical aperture ofthe projection optical system, and k₁ and k₂ are the processcoefficients. Equations (1) and (2) teach that shortening the exposurewavelength λ increases the resolution R, and that increasing thenumerical aperture NA decreases the depth of focus δ.

If the depth of focus δ becomes excessively small, then it will becomedifficult to align the surface of the substrate with the image plane ofthe projection optical system, and there will be a risk of insufficientmargin of focus during the exposure operation. Accordingly, a liquidimmersion method has been proposed, as disclosed in, for example, PCTInternational Publication No. WO99/49504 (Patent Document 1), as amethod to substantially shorten the exposure wavelength and increase thedepth of focus. In this liquid immersion method, the space between thelower surface of the projection optical system and the substrate surfaceis filled with a liquid such as water or any organic solvent to utilizethe fact that the wavelength of the exposure light beam in the liquid is1/n as compared with that in the air (n represents the refractive indexof the liquid, which is about 1.2 to 1.6 in ordinary cases) so that theresolution is improved and the depth of focus is magnified about ntimes. Furthermore, the contents of the above-mentioned Patent Document1 are hereby incorporated by reference in its entirety to the extentpermitted by the laws or regulations of the states designated or electedby the present international patent application.

Incidentally, there is a possibility that vibrations produced by themovement of the substrate stage that holds the substrate, and the like,in the state wherein the liquid is filled between the end surface (theterminal end surface) of the optical member on the most substrate sideof the projection optical system and the substrate surface, willtransmit to the optical member of the terminal end thereof via theliquid, and that the pattern image projected onto the substrate via theprojection optical system and the liquid will unfortunately degrade. Inaddition, there is a possibility that changes in the pressure of thatliquid will apply force to the projection optical system, and willfluctuate the projection optical system, and unfortunately degrade thepattern image projected onto the substrate.

SUMMARY OF THE INVENTION

The present invention was created considering such circumstances, andhas a first object to provide an apparatus that couples two objects sothat the vibration of one object does not transmit to the other object.In addition, the present invention has a second object to provide anexposure apparatus that can suppress the degradation of the patternimage when filling a liquid between a projection optical system and asubstrate and performing an exposure, and a device fabricating methodthat uses this exposure apparatus.

The first aspect of the present invention is an exposure apparatus thatexposes a substrate by filling a liquid between a projection opticalsystem and the substrate, and projecting a pattern image onto thesubstrate via the projection optical system and the liquid, wherein: theprojection optical system includes a first group having an opticalmember that contacts the liquid, and a second group that differs fromthe first group; the first group is supported by a first support member;and the second group is separated from the first group and is supportedby a second support member that is different from the first supportmember.

According to the present aspect, because, of the projection opticalsystem, the first group including the optical member that contacts theliquid and the second group different therefrom are isolated andrespectively supported by the first support member and the secondsupport member, the first group and the second group can bevibrationally isolated. Accordingly, it is possible to prevent thetransmission of vibrations from the first group to the second group, toprevent degradation of the pattern image, and to manufacture a devicewith high pattern accuracy.

The second aspect of the present invention is an exposure apparatus thatexposes a substrate by filling a liquid between a projection opticalsystem and the substrate and projecting a pattern image onto thesubstrate via the projection optical system and the liquid, wherein: theprojection optical system includes a first group has an optical memberthat contacts the liquid, and a second group that is different from thefirst group; and a drive mechanism, which moves the first group, adjuststhe position of the first group with respect to the second group.

According to the present aspect, because, of the projection opticalsystem, the first group including the optical member that contacts theliquid can be positioned at a desired position with respect to thesecond group different from the first group, it is possible to preventdegradation of the pattern image, and to manufacture a high-precisiondevice, even if liquid is filled between the projection optical systemand the substrate.

The third aspect of the present invention is a coupling apparatus thatcouples a first object and a second object, including: a parallel linkmechanism that couples the first object and the second object; and avibration isolating mechanism that is built in the parallel linkmechanism so that vibrations of one of the first object and the secondobject do not transmit to the other.

According to the present aspect, by coupling the first object and thesecond object using the parallel link mechanism in which the vibrationisolating mechanism is built, it is possible to prevent the transmissionof the vibrations (fluctuations) of the one object to the other object.In addition, by driving the parallel link mechanism, it is possible tomaintain and adjust the relative position between the first object andthe second object.

The fourth aspect of the present invention is an exposure apparatus thatexposes a substrate by filling a liquid in at least one part between aprojection optical system and the substrate, and projecting a patternimage onto the substrate via the projection optical system and theliquid, wherein: the projection optical system includes a first grouphaving at least an optical member that contacts the liquid, and a secondgroup disposed between the first group and the pattern; and the exposureapparatus includes: a first holding member that holds the first group; asecond holding member that holds the second group isolated from thefirst holding member; and a frame member that supports the first holdingmember and the second holding member.

According to the present aspect, because the first group including theoptical member that contacts the liquid and the second group differenttherefrom are isolated and respectively supported by the first holdingmember and the second holding member, it is possible to vibrationallyisolate the first group and the second group. Accordingly, it ispossible to prevent the transmission of vibrations, caused by theliquid, from the first holding member holding the first group to thesecond holding member holding the second group, to prevent degradationof the pattern image, and to manufacture a device with high patternaccuracy.

In addition, if, for example, the reference mirror (fixed minor) of theinterferometer system for measuring the position information of thesubstrate stage is affixed to the second holding member, by preventingthe transmission of the vibrations to the second holding member, themeasurement of the position information of the substrate stage and theposition control of the substrate stage based on that measurement resultcan be performed with good accuracy.

The fifth aspect of the present invention is an exposure apparatus thatexposes a substrate by irradiating the substrate with an exposure lightvia a projection optical system and a liquid, wherein: the projectionoptical system includes a first group having an optical member thatcontacts the liquid, and a second group disposed between the first groupand a pattern; and the exposure apparatus includes: a first holdingmember that holds the first group; a second holding member that holdsthe second group isolated from the first holding member; a frame memberfor supporting the first holding member; and a linking mechanismincluding a vibration isolating mechanism for controlling the vibrationsof at least one of the first holding member and the frame member, andthat links the first holding member and the frame member.

According to the present aspect, because the first group including theoptical member that contacts the liquid and the second group differenttherefrom are isolated and respectively supported by the first holdingmember and the second holding member, it is possible to vibrationallyisolate the first group and the second group. Accordingly, it ispossible to prevent the transmission of vibrations, caused by, forexample, the liquid, from the first holding member holding the firstgroup to the second holding member holding the second group, to preventdegradation of the pattern image, and to manufacture a device with highpattern accuracy.

The sixth aspect of the present invention is an exposure apparatus thatexposes a substrate by irradiating the substrate with an exposure lightvia a projection optical system and a liquid, including: a liquidimmersion mechanism that forms an immersion area at only one part on thesubstrate during exposure of the substrate; wherein, the projectionoptical system includes a first group having an optical member thatcontacts the liquid, and a second group disposed between the first groupand a pattern; and the first group and the second group are supportedvibrationally isolated.

According to the present aspect, because the first group including theoptical member that contacts the liquid and the second group differenttherefrom are supported vibrationally isolated, it is possible toprevent the transmission of vibrations, caused by, for example, theliquid, from the first group to the second group, to prevent degradationof the pattern image, and to manufacture a device with high patternaccuracy.

In addition, the seventh aspect of the present invention is a devicefabricating method, wherein an exposure apparatus as recited above isused.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram showing the first embodiment of anexposure apparatus of the present invention.

FIG. 2 shows the positional relationship between a tip portion of aprojection optical system, a liquid supply apparatus, and a liquidrecovery apparatus.

FIG. 3 shows an exemplary arrangement of supply nozzles and recoverynozzles.

FIG. 4 is a schematic diagram showing the first embodiment of a supportstructure of the projection optical system.

FIG. 5 is a schematic diagram showing one example of a support structureof a first group.

FIG. 6 is a schematic diagram showing the second embodiment of thesupport structure of the projection optical system.

FIG. 7 is a schematic block diagram showing the second embodiment of theexposure apparatus of the present invention.

FIG. 8 shows the positional relationship between the tip portion of theprojection optical system, a liquid supply mechanism, and a liquidrecovery mechanism.

FIG. 9 shows an exemplary arrangement of the supply nozzles and therecovery nozzles.

FIG. 10 is a schematic oblique view showing a coupling apparatus.

FIG. 11 is a cross sectional view of a link part that constitutes thecoupling apparatus.

FIG. 12 is a schematic block diagram showing a measuring means thatmeasures the position information of the first group.

FIG. 13 depicts one example of an interferometer.

FIG. 14 is a schematic view for explaining the features of the doublepass interferometer depicted in FIG. 13.

FIG. 15 is a schematic view of the optical path of the interferometer.

FIG. 16 shows another embodiment of the measuring means that measuresthe position information of the first group.

FIG. 17 is a flow chart showing one example of the processes formanufacturing a semiconductor device.

DETAILED DESCRIPTION OF THE INVENTION

The following explains the exposure apparatus and a device fabricatingmethod of the present invention, referencing the drawings. However, thepresent invention is not limited to the embodiments below; for example,the constituent elements of these embodiments may be suitably combined.

First Embodiment of the Exposure Apparatus

FIG. 1 is a schematic block diagram that depicts the first embodiment ofthe exposure apparatus according to the present invention.

In FIG. 1, the exposure apparatus EX includes a mask stage MST thatsupports a mask M; a substrate stage PST that supports a substrate P; anillumination optical system IL that illuminates with an exposure lightEL the mask M supported by the mask stage MST; a projection opticalsystem PL that projects and exposes an image of a pattern of the mask Milluminated by the exposure light EL onto the substrate P supported bythe substrate stage PST; and a control apparatus CONT that collectivelycontrols the overall operation of the exposure apparatus EX.

Here, as an example, the present embodiment explains a case of using, asthe exposure apparatus EX, a scanning type exposure apparatus (aso-called scanning stepper) that, while synchronously moving the mask Mand the substrate P in mutually different directions (oppositedirections) in the scanning direction, exposes the substrate P with thepattern formed on the mask M. In the following explanation, thedirection that coincides with an optical axis AX of the projectionoptical system PL is the Z axial direction, the direction in which themask M and the substrate P synchronously move in the plane perpendicularto the Z axial direction (the scanning direction) is the X axialdirection, and the direction perpendicular to the Z axial direction andthe X axial direction (the non-scanning direction) is the Y axialdirection. In addition, the rotational (inclined) directions around theX, Y, and Z axes are the θX, θY, and θZ directions, respectively.Furthermore, “substrate” herein includes one in which a semiconductorwafer is coated with a photoresist, and “mask” includes a reticlewherein is formed a device pattern that is reduction projected onto thesubstrate.

The exposure apparatus EX of the present embodiment is a liquidimmersion type exposure apparatus that applies the liquid immersionmethod to substantially shorten the exposure wavelength, improve theresolution, as well as substantially increase the depth of focus, andincludes a liquid supply apparatus 1 that supplies a liquid 50 onto thesubstrate P, and a liquid recovery apparatus 2 that recovers the liquid50 on the substrate P. At least during the transfer of the pattern imageof the mask M onto the substrate P, the exposure apparatus EX forms theimmersion area, by the liquid 50 supplied from the liquid supplyapparatus 1, at one part on the substrate P that includes a projectionarea of the projection optical system PL. Specifically, the exposureapparatus EX exposes the substrate P by locally filling the liquid 50between a tip surface (lowest surface) 7 of an optical element 60 of thetip portion of the projection optical system PL and the surface of thesubstrate P; and then projecting the pattern image of the mask M ontothe substrate P via the liquid 50 between this projection optical systemPL and the substrate P, and via the projection optical system PL.

The illumination optical system IL illuminates with the exposure lightEL the mask M supported by the mask stage MST, and includes: an exposurelight source; an optical integrator that uniformizes the intensity ofthe luminous flux emitted from the exposure light source; a condenserlens that condenses the exposure light EL from the optical integrator; arelay lens system; and a variable field stop that sets to a slit shapean illumination region on the mask M illuminated by the exposure lightEL; and the like. The illumination optical system IL illuminates thepredetermined illumination region on the mask M with the exposure lightEL, having a uniform illumination intensity distribution. Examples oflight used as the exposure light EL emitted from the illuminationoptical system IL include: deep ultraviolet light (DUV light), such asbright lines (g, h, and i lines) in the ultraviolet region emitted froma mercury lamp for example, and KrF excimer laser light (248 nmwavelength); and vacuum ultraviolet light (VUV light), such as ArFexcimer laser light (193 nm wavelength) and F, laser light (157 nmwavelength). ArF excimer laser light is used in the present embodiment.

The mask stage MST supports the mask M, and is two dimensionally movablein the plane perpendicular to the optical axis AX of the projectionoptical system PL, i.e., in the XY plane, and is finely rotatable in theOZ direction. A mask stage drive apparatus MSTD, such as a linear motor,drives the mask stage MST. The control apparatus CONT controls the maskstage drive apparatus MSTD. A laser interferometer measures in real timethe position, in the two dimensional direction, and the rotational angleof the mask M on the mask stage MST, and outputs the measurement resultsto the control apparatus CONT. The control apparatus CONT drives themask stage drive apparatus MSTD based on the measurement results of thelaser interferometer, thereby positioning the mask M, which is supportedby the mask stage MST.

The projection optical system PL projection-exposes the pattern of themask M onto the substrate P with a predetermined projectionmagnification β, and includes a plurality of optical elements (lenses),and these optical elements are supported by a lens barrel PK. In thepresent embodiment, the projection optical system PL is a reductionsystem having a projection magnification β of, for example, ¼ or ⅕.Furthermore, the projection optical system PL may be either a unitymagnification system or an enlargement system.

The projection optical system PL includes: the optical element (firstgroup) 60 disposed on the tip side (the substrate P side) thereof andhaving an optical member that contacts the liquid 50; and a projectionoptical system main body (second group) MPL that includes a plurality ofoptical elements disposed between the optical element 60 and the mask M.The lens barrel PK supports the projection optical system main body MPL,and the optical element 60 is supported separated from the lens barrelPK. The details of the support structure of the optical element 60 andthe projection optical system main body MPL will be discussed later.Furthermore, in the present embodiment, the optical element 60 thatconstitutes the first group consists of one optical member (lens).

The substrate stage PST supports the substrate P, and includes: a Zstage 51 that holds the substrate P via a substrate holder, and an XYstage 52 that supports the Z stage 51. A stage base 53 supports thesubstrate stage PST includes the Z stage 51 and the XY stage 52. Asubstrate stage drive apparatus PSTD, such as a linear motor, drives thesubstrate stage PST. The control apparatus CONT controls the substratestage drive apparatus PSTD. By driving the Z stage 51, the position inthe Z axial direction (the focus position) and in the θX and θYdirections of the substrate P held on the Z stage 51 is controlled. Inaddition, by driving the XY stage 52, the position of the substrate P inthe XY direction (the position in a direction substantially parallel tothe image plane of the projection optical system PL) is controlled. Inother words, the Z stage 51 controls the focus position and theinclination angle of the substrate P and aligns the surface of thesubstrate P with the image plane of the projection optical system PL byan auto focus system and an auto leveling system; further, the XY stage52 positions the substrate P in the X axial direction and Y axialdirection. It goes without saying that the Z stage and the XY stage maybe integrally provided.

A movable mirror 54 that moves integrally with the substrate stage PSTis provided on the substrate stage PST (the Z stage 51). In addition, alaser interferometer 55 is provided at a position opposing the movableminor 54. The laser interferometer 55 measures in real time the positionin the two dimensional direction and the rotational angle of thesubstrate P on the substrate stage PST, and outputs the measurementresults to the control apparatus CONT. The control apparatus CONT drivesthe substrate stage drive apparatus PSTD based on the measurementresults of the laser interferometer 55, thereby positioning thesubstrate P supported on the substrate stage PST.

The exposure apparatus EX includes: the liquid supply apparatus 1 thatsupplies the predetermined liquid 50 into a space 56 between the tipsurface (tip surface of optical element 60) 7 of the projection opticalsystem PL and the substrate P; and the liquid recovery apparatus 2 thatrecovers the liquid 50 from the space 56. The liquid supply apparatus 1is for the purpose of filling the liquid 50 in at least one part betweenthe projection optical system PL and the substrate P, and has a tankthat stores the liquid 50, a pressurizing pump, and the like. One end ofa supply pipe 3 is connected to the liquid supply apparatus 1, and asupply nozzle 4 is connected to the other end of the supply pipe 3. Theliquid supply apparatus 1 supplies the liquid 50 into the space 56 viathe supply pipe 3 and the supply nozzle 4.

The liquid recovery apparatus 2 has a suction pump, the tank that storesthe recovered liquid 50, and the like. One end of a recovery pipe 6 isconnected to the liquid recovery apparatus 2, and a recovery nozzle 5 isconnected to the other end part of the recovery pipe 6. The liquidrecovery apparatus 2 recovers the liquid 50 from the space 56 via therecovery nozzle 5 and the recovery pipe 6. When filling the liquid 50into the space 56, the control apparatus CONT drives the liquid supplyapparatus 1, supplies a predetermined amount of the liquid 50 per unitof time into the space 56 via the supply pipe 3 and the supply nozzle 4,and also drives the liquid recovery apparatus 2 and recovers from thespace 56 a predetermined amount of the liquid 50 per unit of time viathe recovery nozzle 5 and the recovery pipe 6. Thereby, the liquid 50 isdisposed in the space 56 between the tip surface 7 of the projectionoptical system PL and the substrate P.

In the present embodiment, pure water is used as the liquid 50. Purewater is capable of transmitting not only ArF excimer laser light, butalso the exposure light EL if set to deep ultraviolet light (DUV light),such as the bright lines (g, h, and i lines) in the ultraviolet regionemitted from, for example, a mercury lamp, and KrF excimer laser light(248 nm wavelength).

FIG. 2 is a front view that depicts the lower portion of the projectionoptical system PL of the exposure apparatus EX, the liquid supplyapparatus 1, the liquid recovery apparatus 2, and the like. A tipportion 60A of the optical element 60 at the lowest end of theprojection optical system PL in FIG. 2 is formed to have rectangularshape which is long in the Y axial direction (the non-scanningdirection), leaving just the portion needed in the scanning direction.During scanning exposure, the pattern image of one part of the mask M isprojected onto the rectangular projection area directly below the tipportion 60A, and, synchronized to the movement of the mask M at a speedV in the −X direction (or the +X direction) with respect to theprojection optical system PL, the substrate P moves at a speed β·V(where β is the projection magnification) in the +X direction (or the −Xdirection) via the XY stage 52. Further, after the exposure of one shotregion is completed, the next shot region moves to the scanning startposition by stepping the substrate P, and the exposure process issubsequently performed sequentially for each shot region by thestep-and-scan system. In the present embodiment, the liquid 50 flowsparallel to and in the same direction as the movement direction of thesubstrate P.

FIG. 3 depicts the positional relationship between the tip portion 60Aof the lens 60 of the projection optical system PL, the supply nozzles 4(4A-4C) that supply the liquid 50 in the X axial direction, and therecovery nozzles 5 (5A, 5B) that recover the liquid 50. In FIG. 3, thetip portion 60A of the lens 60 is a rectangular shape that is long inthe Y axial direction; further, the three supply nozzles 4A-4C aredisposed on the +X side and the two recovery nozzles 5A, 5B are disposedon the X side so that the tip portion 60A of the lens 60 of theprojection optical system PL is interposed therebetween in the X axialdirection. Further, the supply nozzles 4A-4C are connected to the liquidsupply apparatus 1 via the supply pipe 3, and the recovery nozzles 5A,5B are connected to the liquid recovery apparatus 2 via the recoverypipe 6. In addition, supply nozzles 8A-8C and recovery nozzles 9A, 9Bare disposed substantially 180° rotated from the supply nozzles 4A-4Cand the recovery nozzles 5A, 5B. The supply nozzles 4A-4C and therecovery nozzles 9A, 9B are alternately arrayed in the Y axialdirection, the supply nozzles 8A-8C and the recovery nozzles 5A, 5B arealternately arrayed in the Y axial direction, the supply nozzles 8A-8Care connected to the liquid supply apparatus 1 via a supply pipe 10, andthe recovery nozzles 9A, 9B are connected to the liquid recoveryapparatus 2 via a recovery pipe 11.

FIG. 4 is a schematic diagram for explaining the support structure ofthe projection optical system PL.

Furthermore, to simplify the explanation, the liquid 50, the liquidsupply apparatus 1, the liquid recovery apparatus 2, and the like, areomitted from FIG. 4. In FIG. 4, the exposure apparatus EX includes amain frame 42 that supports the projection optical system main body MPL,and a base frame 43 that supports the main frame 42 and the substratestage PST (the Z stage 51 and the XY stage 52). A flange 41 is providedat the outer circumference of the lens barrel PK that holds theprojection optical system main body MPL, and the main frame (secondsupport member) 42 supports the projection optical system main body MPLvia this flange 41.

A vibration isolating apparatus 44 is disposed between the main frame 42and the base frame 43, and the vibration isolating apparatus 44 isolatesthe main frame 42 from the base frame 43 so that vibrations of the baseframe 43 do not transmit to the main frame 42 that holds the projectionoptical system main body MPL. The base frame 43 is installedsubstantially horizontally on the floor surface of the clean room viafoot parts 45.

The stage base (first base member) 53 is supported on the base frame(second base member) 43 via a vibration isolating apparatus 46. Thisvibration isolating apparatus 46 isolates the base frame 43 from thestage base 53 so that vibrations of the base frame 43 do not transmit tothe stage base 53, and so that vibrations of the stage base 53 do nottransmit to the base frame 43.

The substrate stage PST is supported on the stage base 53 in anon-contact manner using air bearings, and the like, and the substratestage PST is two dimensionally movable on the stage base 53 using linearmotors (not shown). A support frame (first support member) 47 isprovided on the stage base 53, and the support frame 47 supports acasing (lens cell) 61 that holds the optical element 60. Thus, thesupport frame 47 that holds the optical element 60 (casing 61) and themain frame 42 that supports the projection optical system main body MPLare isolated via the vibration isolating apparatuses 44, 46 so thatvibrations do not mutually transmit.

Furthermore, in the configuration depicted in FIG. 4, a vibrationisolating apparatus the same as the vibration isolating apparatuses 44,46 may be provided between the support frame 47 and the stage base 53,and an elastic member, such as rubber, may be disposed so thatvibrations that do transmit between the support frame 47 and the stagebase 53 are attenuated.

FIG. 5 is an enlarged view of the vicinity of the optical element 60 ofthe projection optical system PL.

A voice coil motor (drive mechanism) 48 is disposed between the supportframe 47 and the casing 61 that holds the optical element 60, thesupport frame 47 supports the casing 61 via the voice coil motor 48 in anon-contact manner, and the optical element 60 held by the casing 61 ismovable in the Z axial direction by driving the voice coil motor 48. Inaddition, the main frame 42 is provided with an interferometer(measuring apparatus) 71 that receives reflected light from a measuringmirror 49 a affixed to the casing 61 and from a measuring mirror 49 baffixed to the lens barrel PK, and measures the spacing between theprojection optical system main body MPL and the optical element 60.Three voice coil motors 48 are disposed between the casing 61 and thesupport frame 47 at, for example, 120° intervals from one another, andare constituted so that they can each move independently, so that theycan move in the Z axial direction, and so that they can incline withrespect to the projection optical system MPL. Based on the measurementresult of the interferometer 71, the voice coil motor 48 is controlledso that the predetermined positional relationship (predeterminedspacing) between the projection optical system main body MPL and theoptical element 60 is maintained.

The following explains the procedure for using the exposure apparatus EXdiscussed above to expose the pattern of the mask M onto the substrateP.

After the mask M is loaded on the mask stage MST and the substrate P isloaded on the substrate stage PST, the control apparatus CONT drives theliquid supply apparatus 1, and starts the operation to supply liquid tothe space 56. Further, if scanning exposure is performed by moving thesubstrate P in the scanning direction (the −X direction) depicted by anarrow Xa (refer to FIG. 3), then the liquid supply apparatus 1 and theliquid recovery apparatus 2 use the supply pipe 3, the supply nozzles4A-4C, the recovery pipe 6, and the recovery nozzles 5A, 5B to supplyand recover the liquid 50. Namely, when the substrate P moves in the −Xdirection, the liquid 50 is supplied between the projection opticalsystem PL and the substrate P from the liquid supply apparatus 1 via thesupply pipe 3 and the supply nozzles 4 (4A-4C), the liquid 50 is alsorecovered by the liquid recovery apparatus 2 via the recovery nozzles 5(5A, 5B) and the recovery pipe 6, and the liquid 50 thereby flows in the−X direction so that it fills between the optical element 60 and thesubstrate P. On the other hand, if scanning exposure is performed bymoving the substrate P in the scanning direction (the +X direction)depicted by an arrow Xb, then the liquid supply apparatus 1 and theliquid recovery apparatus 2 use the supply pipe 10, the supply nozzles8A-8C, the recovery pipe 11, and the recovery nozzles 9A, 9B to supplyand recover the liquid 50. Namely, when the substrate P moves in the +Xdirection, the liquid 50 is supplied between the projection opticalsystem PL and the substrate P by the liquid supply apparatus 1 via thesupply pipe 10 and the supply nozzles 8 (8A-8C), the liquid 50 is alsorecovered by the liquid recovery apparatus 2 via the recovery nozzles 9(9A, 9B) and the recovery pipe 11, and the liquid 50 thereby flows inthe +X direction so that it fills between the optical element 60 and thesubstrate P. In this case, the liquid 50 can be easily supplied into thespace 56, even if the supplied energy of the liquid supply apparatus 1is small, because the liquid 50 supplied, for example, from the liquidsupply apparatus 1 via the supply nozzles 4 flows so that it is drawninto the space 56 as the substrate P moves in the −X direction. Further,even if the substrate P is scanned in either the +X direction or the −Xdirection by switching the direction in which the liquid 50 flows inaccordance with the scanning direction, the liquid 50 can be filledbetween the tip surface 7 of the optical element 60 and the substrate P,and a high resolution and large depth of focus can thereby be obtained.

Here, a cooling apparatus may be provided that cools a coil part of thevoice coil motor 48 to set a predetermined temperature. In that case,water may be used as the refrigerant for that cooling apparatus, whichmay be shared with part of the temperature regulating apparatus thatsets the liquid 50 to a predetermined temperature.

In addition, the interferometer 71 continuously monitors the spacingbetween the lens barrel PK that holds the projection optical system mainbody MPL and the casing 61 that holds the optical element 60; if thespacing changes due to, for example, vibrations of the substrate stagePST and/or a pressure change in the liquid 50, then, based on themeasurement result from the interferometer 71, the voice coil motor 48moves the optical element 60 held by the casing 61, thereby maintainingthe spacing (positional relationship) between the projection opticalsystem main body MPL and the optical element 60 in a predeterminedstate.

Thus, in the present embodiment, the main frame 42 that supports theprojection optical system main body MPL and the support frame 47 thatholds the optical element 60 are vibrationally isolated, and it istherefore possible to prevent vibrations transmitted to the opticalelement 60 from being transmitted to the projection optical system mainbody MPL. In addition, because the optical element 60 is supported bythe support frame 47 via the voice coil motor 48 in a non-contactmanner, thereby protected against vibrations from the support frame 47,the position in the X axial and Y axial directions is stable, and theposition in the Z axial direction is also controlled by the voice coilmotor 48; therefore, the optical element 60 can be positioned in apredetermined state with respect to the projection optical system mainbody MPL. Accordingly, even if performing an immersion exposure byfilling the liquid 50 between the optical element 60 of the projectionoptical system PL and the substrate P, the desired pattern image can beformed on the substrate P without causing any degradation of the patternimage. In addition, if the lens barrel PK is provided with a referencemirror used with the interferometer 55 to monitor the substrate stagePST as well as with an interferometer (not shown) to monitor the maskstage MST, then vibrations of the optical element 60 do not transmit tothe lens barrel PK, and it is therefore possible to prevent measurementerrors in each of the interferometers.

Furthermore, a plurality of measuring mirrors may be providedrespectively for the projection optical system main body MPL and thecasing 61, and the spacing between the projection optical system mainbody MPL and the casing 61, as well as their relative inclination andtheir relative position in the X axial direction and the Y axialdirection, may also be measured. In addition, based on those measurementresults, the voice coil motor 48 may, for example, incline the opticalelement 60, move the optical element 60 in the X axial direction and/orthe Y axial direction. In addition, the present embodiment isconstituted to move the optical element 60, but may be constituted toMove the projection optical system main body MPL. In addition, if theprojection state (imaging state) of the pattern image projected on thesubstrate P changes due to fluctuations in the optical element 60, thena part of the plurality of optical members that constitute theprojection optical system main body MPL may be moved so as to compensatefor changes in the projection state.

Furthermore, in the first embodiment discussed above, the interferometersystem (49 a, 49 b, 71) is used as the measuring apparatus, but ameasuring apparatus employing another system may be used provided thatit can measure the positional relationship between the projectionoptical system main body MPL and the optical element 60 with apredetermined accuracy. For example, instead of the interferometersystem discussed above, it is acceptable to use a measuring apparatusthat optically measures the relative position information of measurementmarks disposed respectively on the lens barrel PK and the casing 61.

FIG. 6 is a schematic diagram that depicts another embodiment of thesupport structure of the projection optical system.

The present embodiment differs from the embodiment of the supportstructure of the projection optical system explained referencing FIG. 14on the point that a support frame 47′ that supports the casing 61 thatholds the optical element 60 is affixed to the base frame 43. In thepresent embodiment as well, the main frame 42 that supports theprojection optical system main body MPL and the support frame 47′ thatholds the optical element 60 are vibrationally isolated, and vibrationstransmitted to the optical element 60 thereby do not transmit to theprojection optical system main body MPL, and the positional relationshipbetween the projection optical system main body MPL and the opticalelement 60 is also maintained in a predetermined state; therefore, thedesired pattern image can be formed on the substrate P without causingdegradation of the pattern image, even if performing an immersionexposure by filling the liquid 50 between the optical element 60 of theprojection optical system PL and the substrate P.

Furthermore, if the projection optical system main body MPL and theoptical element 60 are vibrationally isolated, then the respectivesupport member (frame) is not limited to the embodiments discussedabove.

In addition, in the abovementioned embodiments, the casing 61 isconstituted so that it holds only one optical element 60, but may hold aplurality of optical elements that includes the optical element 60. Inaddition, in embodiments discussed above, the projection optical systemPL is divided into two groups: the optical element 60, and theprojection optical system main body MPL between the mask M and theoptical element 60; however, it may be separated into three or moregroups, and the relative position of the first group, including theoptical element 60, and the groups not adjacent to that first group maybe maintained in a predetermined state.

The above embodiments are not particularly limited to the nozzleconfigurations discussed above, e.g., the liquid 50 may be supplied andrecovered by two pairs of nozzles on the long sides of the tip part 60A.Furthermore, in this case, the supply nozzles and the recovery nozzlesmay be disposed so that they are arrayed vertically in order to enablethe supply and recovery of the liquid 50 from either the +X direction orthe −X direction.

Second Embodiment of the Exposure Apparatus

FIG. 7 is a schematic block diagram that depicts the second embodimentof the exposure apparatus according to the present invention.

In FIG. 7, an exposure apparatus EX2 includes a mask stage MST2 thatsupports a mask M2, a substrate stage PST2 that supports a substrate P2,an illumination optical system IL2 that illuminates the mask M2supported by the mask stage MST2 with exposure light EL2, a projectionoptical system PL2 that projects and exposes the pattern image of themask M2 illuminated by the exposure light EL2 onto the substrate P2supported by the substrate stage PST2, and a control apparatus CONT2that performs overall control of the operation of the entire exposureapparatus EX2. Furthermore, the exposure apparatus EX2 includes a maincolumn 103 that supports the mask stage MST2 and the projection opticalsystem PL2. The main column 103 is installed on the base plate 104 whichis placed horizontally upon the floor surface. An upper side step part(upper side support part) 103A and a lower side step part (lower sidesupport part) 103B that protrude inwardly are formed in the main column103.

The exposure apparatus EX2 of the present embodiment is a liquidimmersion type exposure apparatus that applies the liquid immersionmethod to substantially shorten the exposure wavelength, improve theresolution, as well as substantially increase the depth of focus, andincludes a liquid supply mechanism 110 that supplies a liquid 101 ontothe substrate P2, and a liquid recovery mechanism 120 that recovers theliquid 101 on the substrate P2. At least during the transfer of thepattern image of the mask M2 onto the substrate P2, the exposureapparatus EX2 forms an immersion area AR2, by the liquid 101 suppliedfrom the liquid supply mechanism 110, at one part on the substrate P2that includes a projection area AR1 of the projection optical systemPL2. Specifically, the exposure apparatus EX2 exposes the substrate P2by locally filling the liquid 101 between an optical member (opticalelement) 102 of the tip part (terminal end part) of the projectionoptical system PL2 and the surface of the substrate P2; and thenprojecting the pattern image of the mask M2 onto the substrate P2 viathe liquid 101 between the projection optical system PL2 and thesubstrate P2, and via the projection optical system PL2.

As an example, the present embodiment explains a case of using, as theexposure apparatus EX2, a scanning type exposure apparatus (a so-calledscanning stepper) that, while synchronously moving the mask M2 and thesubstrate P2 in mutually different directions (opposite directions) inthe scanning direction, exposes the substrate P2 with the pattern formedon the mask M2. In the following explanation, the direction thatcoincides with an optical axis AX2 of the projection optical system PL2is the Z axial direction, the direction in which the mask M2 and thesubstrate P2 synchronously move in the plane perpendicular to the Zaxial direction (the scanning direction) is the X axial direction, andthe direction perpendicular to the Z axial direction and the X axialdirection (the non-scanning direction) is the Y axial direction. Inaddition, the rotational (inclined) directions around the X, Y, and Zaxes are the θX, θY, and θZ directions, respectively. Furthermore,“substrate” herein includes one in which a semiconductor wafer is coatedwith a photoresist, which is a photosensitive material, and “mask”includes a reticle wherein is formed a device pattern that is reductionprojected onto the substrate.

The illumination optical system IL2 is supported by a support column 105fixed to the upper part of the main column 103. The illumination opticalsystem IL2 illuminates with the exposure light EL2 the mask M2 supportedby the mask stage MST2, and includes: an exposure light source; anoptical integrator that uniformizes the intensity of the luminous fluxemitted from the exposure light source; a condenser lens that condensesthe exposure light EL2 from the optical integrator; a relay lens system;a variable field stop that sets to a slit shape an illumination regionon the mask M2 illuminated by the exposure light EL2; and the like. Theillumination optical system IL2 illuminates the predeterminedillumination region on the mask M2 with the exposure light EL2, having auniform illumination intensity distribution. Examples of light used asthe exposure light EL2 emitted from the illumination optical system IL2include: deep ultraviolet light (DUV light), such as bright lines (g, h,and i lines) in the ultraviolet region emitted from a mercury lamp forexample, and KrF excimer laser light (248 nm wavelength); and vacuumultraviolet light (VUV light), such as ArF excimer laser light (193 nmwavelength) and F₂ laser light (157 nm wavelength). ArF excimer laserlight is used in the present embodiment.

In the present embodiment, pure water is used as the liquid 101. Purewater is capable of transmitting not only ArF excimer laser light, butalso deep ultraviolet light (DUV light), such as the bright lines (g, h,and i lines) in the ultraviolet region emitted from, for example, amercury lamp, and KrF excimer laser light (248 nm wavelength).

The mask stage MST2 supports the mask M2, and includes an aperture 134Aat its center part through which passes the pattern image of the maskM2. A mask base plate 131 is supported on the upper side step part 103Aof the main column 103 via a vibration isolating unit 106. An aperture134B through which passes the pattern image of the mask M2 is alsoformed at the center part of the mask base plate 131. A plurality of gasbearings (air bearings) 132, which are non-contact bearings, is providedat the lower surface of the mask stage MST2. The mask stage MST2 issupported by the air bearings 132 in a non-contact manner with respectto an upper surface (guide surface) 131A of the mask base plate 131, andis two dimensionally movable by the mask stage drive mechanism, such asa linear motor, within a plane perpendicular to the optical axis AX2 ofthe projection optical system PL2, i.e., within the XY plane, and isfinely rotatable about the θZ direction. A movable minor 135 is providedat a predetermined position on the +X side on the mask stage MST2. Inaddition, a laser interferometer 136 is provided at a position opposingthe movable minor 135. Likewise, although not shown, a movable minor isalso provided on the +Y side on the mask stage MST2, and a laserinterferometer is provided at a position opposing thereto. The laserinterferometer 136 measures in real time the position, in the twodimensional direction, and the rotational angle in the θZ direction(depending on the case, also including the rotational angles in the θX,θY directions) of the mask M2 on the mask stage MST2, and outputs themeasurement results to the control apparatus CONT2. The controlapparatus CONT2 drives the mask stage drive mechanism based on themeasurement results of the laser interferometer 136, thereby positioningthe mask M2, which is supported by the mask stage MST2.

The projection optical system PL2 projects and exposes the pattern ofthe mask M2 onto the substrate P2 with a predetermined projectionmagnification β. In the present embodiment, the projection opticalsystem PL2 is a reduction system having a projection magnification β offor example, ¼ or ⅕. Furthermore, the projection optical system PL2 maybe either a unity magnification system or an enlargement system. Theprojection optical system PL2 includes: the optical element (firstgroup) 102 disposed on the terminal side (the substrate P2 side) thereofand that contacts the liquid 101; and an optical group (second group)MPL2 that includes a plurality of optical elements disposed between theoptical member 102 and the mask M2 having a pattern. Furthermore, in thepresent embodiment, the first group has only the optical member 102,i.e., only one lens element (optical element). A metal lens cell (firstholding member) LS2 holds the lens element 102. The lens cell LS2 ismade of metal, and a spring mechanism (not shown) is interposed betweenthe lens cell LS2 and the lens element 102. Further, a lens barrel(second holding member) PK2 holds the optical group MPL2. The lens cellLS2 and the lens barrel PK2 are isolated.

An outer circumferential part of the lens barrel PK2 is provided with aflange part FLG2. In addition, a lens barrel base plate 108 is supportedvia a vibration isolating unit 107 on the lower side step part 103B ofthe main column 103. Furthermore, engaging the flange part FLG2 to thelens barrel base plate 108 causes the lens barrel PK2, which holds theoptical group MPL2, to be supported by the lens barrel base plate (framemember) 108.

The lens cell LS2 that holds the lens element 102 is coupled to the lensbarrel base plate 108 by a coupling apparatus 160, which is discussed indetail later, and supported by the lens barrel base plate 108 via thecoupling apparatus 160. The lens element 102 held by the lens cell LS2is movable by the coupling apparatus 160 with respect to the opticalgroup MPL2 held by the lens barrel PK2.

Each of the plurality of optical elements that constitutes theprojection optical system PL2 is made of fluorite or quartz, andaspherical surface polishing process is applied to the curved surface ofa part of the optical elements. In particular, if the lens element 102is made of fluorite, then this fluorite will unfortunately corrode dueto water if left as is over a long period of time, and it is thereforecoated beforehand with an appropriate thin film to increase itsaffinity. Thereby, the liquid 101 can be made to closely contact thesubstantially entire surface of the liquid contact surface of the lenselement 102, and the optical path between the lens element 102 and thesubstrate P2 can thereby be reliably filled with the liquid 101.Furthermore, the lens element 102 may also be made of quartz, which hasa high affinity for water. In addition, if the liquid contact surface ofthe lens element 102 is treated to make it hydrophilic (lyophilic), suchas with a coating, and its affinity for water is thereby increased, thenit may have a special film structure (for example, a film that changesits molecular arrangement if an electric field is applied, or a filmthat increases in temperature if a minute electric current flows) sothat, in a dried state wherein the water has been removed from theimmersion area AR2, moisture from the liquid contact surface of the lenselement 102 rapidly escapes.

The substrate stage PST2 is movable while holding the substrate P2 bysuction via a substrate holder PH2, and a plurality of gas bearings (airbearing) 142, which are non-contact bearings, is provided at the lowersurface thereof. A substrate base plate 141 is supported on a base plate104 via a vibration isolating unit 109. A substrate stage PST2 issupported by the air bearings 142 in a non-contact manner with respectto an upper surface (guide surface) 141A of the substrate base plate141, and is finely rotatable in the θZ direction and two dimensionallymovable within a plane perpendicular to the optical axis AX2 of theprojection optical system PL2, i.e., within the XY plane, by a substratestage drive mechanism, such as a linear motor. Furthermore, thesubstrate stage PST2 is also movable in the Z axial direction, the θXdirection, and the θY direction. The control apparatus CONT2 controlsthe substrate stage drive mechanism. The substrate stage PST2 aligns thesurface of the substrate P2 with the image plane of the projectionoptical system PL2 by an auto focus system and an auto leveling system,by controlling the focus position (Z position) and the inclination angleof the substrate P2, and also positions the substrate P2 in the X axialdirection and the Y axial direction.

A movable minor 180 that moves integrally with the substrate stage PST2is provided at a predetermined position on the +X side on the substratestage PST2 (substrate holder PH2), and a reference mirror (fixed minor)181 is provided at a predetermined position on the +X side of the lensbarrel PK2. In addition, a laser interferometer 182 is provided at aposition opposing the movable mirror 180. The laser interferometer 182irradiates the movable mirror 180 with a measuring beam (measuringlight), and also irradiates the reference mirror 181 with a referencebeam (reference light) via minors 183A, 183B. The reflected light ofeach of the movable mirror 180 and the reference mirror 181 based on theirradiated measuring beam and the reference beam is received by a lightreceiving part of the laser interferometer 182. The laser interferometer182 causes these light beams to interfere, and measures the amount ofchange in the optical path length of the measuring beam, using theoptical path length of the reference beam as a reference, and theposition (coordinate) and/or displacement of the movable mirror 180,using the reference minor 181 as a reference. The lens barrel PK2supports the reference minor 181, and the substrate holder PH2(substrate stage PST2) supports the movable mirror 180. Likewise,although not shown, a movable mirror and a reference mirror are alsoprovided on the +Y side of the lens barrel PK2 on the substrate stagePST2 respectively, and a laser interferometer is provided at a positionopposing thereto. The laser interferometer 182 measures in real time theposition in the two dimensional direction and the rotational angle ofthe substrate P2, and the measurement results are outputted to thecontrol apparatus CONT2. The control apparatus CONT2 moves and positionsthe substrate P2 supported by the substrate stage PST2 by driving thesubstrate stage drive mechanism, which includes a linear motor, based onthe measurement results of the laser interferometer 182.

In addition, an auxiliary plate 143 that surrounds the substrate P2 isprovided on the substrate stage PST2 (substrate holder PH2). Theauxiliary plate 143 has a flat surface of substantially the same heightas the surface of the substrate P2 held by the substrate holder PH2. Theliquid 101 can be held below the projection optical system PL2 using theauxiliary plate 143 even when exposing the edge area of the substrateP2.

The substrate stage PST2 is supported freely movable in the X axialdirection by an X guide stage 144. The substrate stage PST2 is movableby a predetermined stroke in the X axial direction by an X linear motor147 while being guided by the X guide stage 144. The X linear motor 147includes a stator 147A provided in the X guide stage 144 extending inthe X axial direction, and a slider 147B provided corresponding to thestator 147A and fixed to the substrate stage PST2. Furthermore, thesubstrate stage PST2 moves in the X axial direction by driving theslider 147B with respect to the stator 147A. Here, the substrate stagePST2 is supported, in a non-contact manner, by a magnetic guideincluding an actuator and a magnet that maintains a gap of apredetermined size in the Z axial direction with respect to the X guidestage 144. The X linear motor 147 moves the substrate stage PST2 in theX axial direction in a state supported by the X guide stage 144 in anon-contact manner.

The ends of the X guide stage 144 in the longitudinal direction are eachprovided with one of the pair of Y linear motors 148 capable of movingthis X guide stage 144 along with the substrate stage PST2 in the Yaxial direction. The Y linear motors 148 respectively include sliders148B, provided at both ends of the X guide stage 144 in the longitudinaldirection, and stators 148A provided corresponding to these sliders148B.

Furthermore, the X guide stage 144 along with the substrate stage PST2moves in the Y axial direction by driving the sliders 148B with respectto the stators 148A. In addition, the X guide stage 144 can also berotated in the OZ direction by adjusting the respective drives of the Ylinear motors 148. Accordingly, the substrate stage PST2 is movablesubstantially integrally with the X guide stage 144 in the Y axialdirection and the OZ direction by these linear motors 148.

Guides 149 that guide the movement of the X guide stage 144 in the Yaxial direction are provided respectively on both sides of the substratebase plate 141 in the X axial direction. Each guide part 149 issupported on the base plate 104. Further, a U-shaped guided member 145is provided on the lower surface of the X guide stage 144 at each end ofthe X guide stage 144 in the longitudinal direction. Each guide part 149is provided so that it engages with the respective guided member 145,and so that the upper surface (the guide surface) of each guide part 149opposes the inner surface of the guided member 145. The guide surface ofeach guide part 149 is provided with a gas bearing (air bearing) 146,which is a non-contact bearing, and the X guide stage 144 is supportedby the guide surfaces of the guide parts 149 in a non-contact manner.

FIG. 8 is an enlarged view that depicts the vicinity of the liquidsupply mechanism 110, the liquid recovery mechanism 120, and the tipportion of the projection optical system PL2.

The liquid supply mechanism 110 supplies the liquid 101 between theprojection optical system PL2 and the substrate P2, and includes aliquid supply section 111 capable of feeding the liquid 101; and supplynozzles 114, which are connected to the liquid supply section 111 via asupply pipe 115, that supply the liquid 101 fed from this liquid supplysection 111 onto the substrate P2. The supply nozzles 114 are disposedproximate to the surface of the substrate P2. The liquid supply section111 includes a tank that stores the liquid 101, a pressurizing pump, atemperature regulator that adjusts the temperature of the liquid 101 tobe supplied, and the like, and supplies the liquid 101 onto thesubstrate P2 via the supply pipe 115 and the supply nozzles 114. Thecontrol apparatus CONT2 controls the operation by which the liquidsupply section 111 supplies the liquid, and can control the amount ofliquid supplied per unit of time onto the substrate P2 by the liquidsupply section 111.

The liquid recovery mechanism 120 recovers the liquid 101 on thesubstrate P2 supplied by the liquid supply mechanism 110, and includesrecovery nozzles 121 disposed proximate to the surface of the substrateP2, and a liquid recovery section 125 connected to the recovery nozzles121 via a recovery pipe 124. The liquid recovery section 125 includes asuction pump, and a tank that can store the recovered liquid 101. Theliquid 101 recovered by the liquid recovery section 125 is, for example,discharged, or cleaned and returned to the liquid supply section 111,and the like, for reuse.

When forming the immersion area AR2 on the substrate P2, the controlapparatus CONT2 drives the liquid supply section 111 to supply apredetermined amount of the liquid 101 per unit of time via the supplypipe 115 and the supply nozzles 114, and also drives the liquid recoverysection 125 to recover a predetermined amount of the liquid 101 per unitof time via the recovery nozzles 121 and the recovery pipe 124. Thereby,an immersion area AR2 of the liquid 101 is formed between the lenselement 102 of the terminal end part of the projection optical systemPL2 and the substrate P2.

Furthermore, as depicted in the partial cross sectional views of FIG. 7and FIG. 8, the liquid supply mechanism 110 and the liquid recoverymechanism 120 are supported and isolated from the lens barrel base plate108. Thereby, vibrations produced by the liquid supply mechanism 110 andthe liquid recovery mechanism 120 do not transmit to the projectionoptical system PL2 via the lens barrel base plate 108.

FIG. 9 is plan view that depicts the positional relationship between theliquid supply mechanism 110, the liquid recovery mechanism 120, and theprojection area AR1 of the projection optical system PL2. The projectionarea AR1 of the projection optical system PL2 is a rectangular shape(slit shape) that is long in the Y axial direction; further, the threesupply nozzles 114A-114C are disposed on the +X side and the tworecovery nozzles 121A, 121B are disposed on the X side so that theprojection area AR1 is interposed therebetween in the X axial direction.Furthermore, the supply nozzles 114A-114C are connected to the liquidsupply section 111 via the supply pipe 115, and the recovery nozzles121A, 121B are connected to the liquid recovery section 125 via therecovery pipe 124. In addition, supply nozzles 114′-114C′ and recoverynozzles 121A′, 121 a are disposed in an arrangement substantially 180°rotated from the supply nozzles 114A-114C and the recovery nozzles 121A,121B. The supply nozzles 114A-114C and the recovery nozzles 121A′, 121B′are alternately arrayed in the Y axial direction, the supply nozzles114A′-114C′ and the recovery nozzles 121A, 121B are alternately arrayedin the Y axial direction, the supply nozzles 114A′-114C′ are connectedto the liquid supply section 111 via a supply pipe 115′, and therecovery nozzles 121A′, 121B′ are connected to the liquid recoverysection 125 via a recovery pipe 124′.

FIG. 10 is an oblique view that depicts the coupling apparatus 160 thatcouples the lens cell LS2 and the lens barrel base plate 108.

The coupling apparatus 160 includes a parallel link mechanism providedwith a plurality of link parts 161 arranged in a row and each having anactuator unit 162. In the present embodiment, the coupling apparatus 160is a six degrees of freedom parallel link mechanism including six linkparts 161, and the lens cell LS2 is kinematically supported. In thepresent embodiment, the link parts 161 are disposed at substantially120° intervals, two at a time as pairs. Furthermore, the six link parts161 may be arranged at equal intervals, or may be arranged at unequalintervals.

Each link part 161 includes a first linking member 164 linked to thelens cell LS2 via a spherical bearing 163, and a second linking member166 linked to the lens barrel base plate 108 via a spherical bearing165. The first and second linking members 164, 166 are shaft shapedmembers, and are provided movable in the axial direction with respect toa tubular member 167 that constitutes the actuator unit 162.Furthermore, the first and second linking members 164, 166 can be movedin the axial direction with respect to the tubular member 167 of theactuator unit 162 by driving the actuator unit 162, and thereby the linkpart 161 can maintain or change (expand or contract) the spacing betweenthe spherical bearing 163 and the spherical bearing 165.

By expanding and contracting each of the link parts 161, the couplingapparatus 160 can maintain or adjust the attitude of the lens cell LS2with respect to the lens barrel base plate 108. Because the lens barrelPK2 that holds the optical group MPL2 is supported by the lens barrelbase plate 108, and the lens element 102 is held by the lens cell LS2,the coupling apparatus 160 can substantially maintain or adjust theattitude of the lens element 102 with respect to the optical group MPL2by expanding or contracting each of the link parts 161.

FIG. 11 is a cross sectional view of the link part 161.

In FIG. 11, the link part 161 includes the tubular member 167, and thefirst and second linking members 164, 166, which are shaft shapedmembers provided movable (retractable) with respect to the tubularmember 167. The spherical bearings 163, 165 are provided respectively attip parts 164A, 166A of the first and second linking members 164, 166.Gas bearings (air bearings) 168, 169, which are non-contact bearings,are disposed respectively between the tubular member 167 and the firstand second linking members 164, 166. Furthermore, other systems ofbearings that use magnetism and the like can also be used as thenon-contact bearings. Two air bearings 168 are provided arranged in arow in the axial direction at a position opposing the first linkingmember 164 on the inner surface of the tubular member 167. Likewise, twoair bearings 169 are provided lined up in the axial direction at aposition opposing the second linking member 166 on the inner surface ofthe tubular member 167. These air bearings 168, 169 are tubularlyprovided along the inner surface of the tubular member 167. A gas supplysource 171 supplies compressed gas (air) to the air bearings 168, 169via a passageway 170 formed inside the tubular member 167. The first andsecond linking members 164, 166 are supported by the air bearings 168,169 in a non-contact manner with respect to the tubular member 167.

A first voice coil motor 172 is disposed between the first linkingmember 164 and the tubular member 167 as a drive mechanism that drivesthe first linking member 164. In the present embodiment, a coil 172A isprovided along the inner surface of the tubular member 167 and a magnet172B is provided along an outer circumferential surface of the firstlinking member 164, both constituting the first voice coil motor 172.Furthermore, driving the first voice coil motor 172 generates Lorentz'sforce, and the first linking member 164 supported by the tubular member167 in a non-contact manner is movable in the axial direction thereof.

Likewise, a second voice coil motor 173 is disposed between the secondlinking member 166 and the tubular member 167 as a drive mechanism thatdrives the second linking member 166. A coil 173A is provided along theinner surface of the tubular member 167 and a magnet 173B is providedalong the outer circumferential surface of the second linking member166, both constituting the second voice coil motor 173. Furthermore,driving the second voice coil motor 173 generates Lorentz's force, andthe second linking member 166 supported by the tubular member 167 in anon-contact manner is movable in the axial direction thereof.

The link part 161 uses Lorentz's force produced by the voice coil motors172, 173 to move the first and second linking members 164, 166, and thedistance between the tip part 164A of the first linking member 164 andthe tip part 166A of the second linking member 166 can thereby bechanged. In other words, the link part 161 is expandable andcontractible.

The first linking member 164 and the second linking member 166 arelinked in a non-contact manner, and a space 174 therebetween isconnected to a vacuum apparatus 176 via a passageway 175 formed in thetubular member 167.

By driving the vacuum apparatus 176, a negative pressure is applied tothe space 174. Thereby, in a state wherein the lens cell LS2 is linkedto the first linking member 164 and the lens barrel base plate 108 islinked to the second linking member 166, even if the first linkingmember 164 receives a force, such as the weight of the lens cell LS2 andits own weight of the first linking member 164, in a direction away fromthe second linking member 166, a counterforce acts to pull together thefirst linking member 164 and second linking member 166 which are linkedin a non-contact manner. Furthermore, if the lens cell LS2 is held withthe projection optical system PL2 turned upside down, then a positivepressure may be applied to the space 174 between the first linkingmember 164 and the second linking member 166.

A first encoder 177, which is a position measuring apparatus thatmeasures the position information of the first linking member 164 withrespect to the tubular member 167, is provided at a predeterminedposition disposed at a rear end part 164B of the first linking member164, i.e., at the space 174 of the first linking member 164. Likewise, asecond encoder 178, which is a position measuring apparatus thatmeasures the position information of the second linking member 166 withrespect to the tubular member 167, is provided at a predeterminedposition disposed at the rear end part 166B of the second linking member166, i.e., at the space 174 of the second linking member 166. Themeasurement result of each of the first and second encoders 177, 178 isoutputted to the control apparatus CONT2. Further, because the relativeposition information between the first linking member 164 and thetubular member 167 is measured by the first encoder 177, and therelative position information between the second linking member 166 andthe tubular member 167 is measured by the second encoder 178, thecontrol apparatus CONT2 can obtain the position information of the firstlinking member 164 with respect to the second linking member 166 basedon the measurement results of these first and second encoders 177, 178.The first linking member 164 is linked to the lens cell LS2 that holdsthe lens element 102, and the second linking member 166 is linked to thelens barrel base plate 108 that supports the lens barrel PK2 that holdsthe optical group MPL2. Accordingly, by obtaining the positioninformation of the first linking member 164 with respect to the secondlinking member 166, the control apparatus CONT2 can substantially obtainthe position information of the lens cell LS2 (the lens element 102)with respect to the lens barrel base plate 108 (the optical group MPL2).

Further, based on the measurement results of the first and secondencoders 177, 178 provided in each of the six link parts 161, thecontrol apparatus CONT2 obtains the attitude information of the lenscell LS2 (lens element 102) with respect to the lens barrel base plate108 (optical group MPL2).

When expanding and contracting each of the link parts 161 in the presentembodiment (when changing the distance between the tip part 164A of thefirst linking member 164 and the tip part 166A of the second linkingmember 166), only the first voice coil motor 172 is driven, and thesecond voice coil motor 173 is not driven. Further, because the airbearing 168 supports the first linking member 164 in a non-contactmanner with respect to the tubular member 167, when driving the voicecoil motor 172 in order to change the distance between the tip part 164Aof the first linking member 164 and the tip part 166A of the secondlinking member 166, the tubular member 167 moves in a direction theopposite of the movement direction of the first linking member 164 byjust the amount of that applied drive impulse divided by the mass of thetubular member 167. This movement of the tubular member 167 offsets thereaction force which is generated with the drive of the voice coil motor172 in order to move the first linking member 164, or in order tomaintain the attitude of the first linking member 164 after themovement. In other words, this tubular member 167 functions as aso-called counter mass. The action of the tubular member 167 as acounter mass absorbs the vibrations produced by the movement of the lenscell LS2 via the first linking member 164, and those vibrationstherefore do not transmit to the lens barrel base plate 108.

In addition, when, for example, a force is applied to the lens cell LS2by the liquid 101, the voice coil motor 172 drives to maintain theattitude of the lens cell LS2, i.e., so that the first linking member164 does not move. At this time, the tubular member 167 moves in thedirection the reverse of the direction in which the voice coil motor 172applied a force to the first linking member 164, and the reaction forcewhich is generated with the drive of the voice coil motor 172 is therebyoffset. In this case as well, the action of the tubular member 167absorbs the vibrations produced by the lens cell LS2, and it istherefore possible to prevent the transmission of those vibrations tothe lens barrel base plate 108.

The following explains the procedure for using the exposure apparatusEX2 discussed above to expose the pattern of the mask M2 onto thesubstrate P2.

After the mask M2 is loaded onto the mask stage MST2 and the substrateP2 is loaded onto the substrate stage PST2, the control apparatus CONT2drives the liquid supply section 111 of the liquid supply mechanism 110,and supplies a predetermined amount of liquid 101 per unit of time ontothe substrate P2 via the supply pipe 115 and the supply nozzles 114. Inaddition, the control apparatus CONT2 drives the liquid recovery section125 of the liquid recovery mechanism 120 as the liquid supply mechanism110 supplies the liquid 101, and recovers a predetermined amount of theliquid 101 per unit of time via the recovery nozzles 121 and therecovery pipe 124. Thereby, the immersion area AR2 of the liquid 101 isformed between the lens element 102 of the tip part of the projectionoptical system PL2 and the substrate P2. Furthermore, the controlapparatus CONT2 illuminates the mask M2 with the exposure light EL2 bythe illumination optical system 1L2, and projects an image of thepattern of the mask M2 onto the substrate P2 via the projection opticalsystem PL2 and the liquid 101.

During a scanning exposure, the pattern image of part of the mask M2 isprojected onto the projection area AR1, and the substrate P2 moves inthe +X direction (or −X direction) at a speed β·V (where β is theprojection magnification) via the substrate stage PST2 synchronized tothe movement of the mask M2 at the speed V in the −X direction (or +Xdirection) with respect to the projection optical system PL2. Further,after the exposure of one shot region is completed, the next shot regionmoves to the scanning start position by the stepping of the substrateP2, and the exposure process is successively performed subsequently foreach shot region by the step-and-scan system. In the present embodiment,the liquid 101 is flowed in a direction parallel to and identical to themovement direction of the substrate P2. In other words, if the scanningexposure is performed by moving the substrate P2 in the scanningdirection (the −X direction) depicted by an arrow Xa2 (refer to FIG. 9),then the liquid supply mechanism 110 and the liquid recovery mechanism120 use the supply pipe 115, the supply nozzles 114A-114C, the recoverypipe 124, and the recovery nozzles 121A, 121B to supply and recover theliquid 101. In other words, when the substrate P moves in the −Xdirection, the supply nozzles 114 (114A-114C) supply the liquid 101between the projection optical system PL2 and the substrate P2, therecovery nozzles 121 (121A, 121B) recover the liquid 101 on thesubstrate P2, and the liquid 101 thereby flows in the −X direction sothat it fills between the lens element 102 at the tip portion of theprojection optical system PL2 and the substrate P2. On the other hand,if the scanning exposure is performed by moving the substrate P2 in thescanning direction (the +X direction) depicted by an arrow Xb2 (refer toFIG. 9), then the liquid supply mechanism 110 and the liquid recoverymechanism 120 use the supply pipe 115′, the supply nozzles 114A′-114C′,the recovery pipe 124′, and the recovery nozzles 121A′, 121B′ to supplyand recover the liquid 101. In other words, when the substrate P movesin the +X direction, the supply nozzles 114′ (114A′-114C′) supply theliquid 101 between the projection optical system PL2 and the substrateP2, the recovery nozzles 121′ (121A′, 121B′) recover the liquid 101, andthe surrounding gas, on the substrate P2, and the liquid 101 therebyflows in the +X direction so that it fills between the lens element 102at the tip portion of the projection optical system PL2 and thesubstrate P2. In this case, the liquid 101 can be easily suppliedbetween the lens element 102 and the substrate P2, even if the suppliedenergy of the liquid supply mechanism 110 (liquid supply part 111) issmall, because the liquid 101 supplied, for example, via the supplynozzles 114, flows so that it is drawn between the lens element 102 andthe substrate P2 as the substrate P2 moves in the −X direction. Further,even if the substrate P2 is scanned in either the +X direction or the −Xdirection by switching the direction in which the liquid 101 flows inaccordance with the scanning direction, the liquid 101 can be filledbetween the lens element 102 and the substrate P2, and a high resolutionand large depth of focus can thereby be obtained.

Here, the vibration component produced by the substrate P2 side due tothe movement of the substrate stage PST2 in the XY direction to performscanning and exposure, and/or due to the movement in the Z axialdirection and the inclined directions (θX, θY directions) to performfocus-leveling adjustment, may be transmitted to the lens element 102via the liquid 101 of the immersion area AR2. In addition, it is alsoconceivable that the viscous resistance of the liquid 101 in theimmersion area AR2 may move the lens element 102 when scanning thesubstrate P2. In that case, there is a possibility that the patternimage projected onto the substrate P2 via the projection optical systemPL2 and the liquid 101 will unfortunately degrade.

Incidentally, because the lens element 102, which contacts the liquid101, and the optical group MPL2 are isolated and held by the lens cellLS2 and the lens barrel PK2, respectively, the lens element 102 and theoptical group MPL2 can be vibrationally isolated. Accordingly, it ispossible to suppress the transmission to the optical group MPL2 ofvibrations transmitted to the lens element 102.

When vibrations act upon the lens element 102, the lens element 102moves, and changes its relative position with the optical group MPL2,and there is consequently a possibility of inviting degradation of thepattern image therewith. At this time, the control apparatus CONT2obtains the attitude information of the lens element 102 with respect tothe optical group MPL2 based on the measurement results of the first andsecond encoders 177, 178 provided in each of the link parts 161 thatconstitute the coupling apparatus 160.

The control apparatus CONT2 can maintain in a desired state the position(attitude) of the lens element 102 with respect to the optical groupMPL2 by driving the first voice coil motor 172 of each of the link parts161 based on the obtained attitude information. In other words, thecontrol apparatus CONT2 performs feedback control wherein the firstvoice coil motor 172 is driven to maintain in a desired state theattitude of the lens element 102 with respect to the optical group MPL2based on the measurement results of the first and second encoders 177,178. Thereby, even if vibrations act upon the lens element 102, the lenselement 102 moves, and thereby the relative position with respect to theoptical group MPL2 is made to change, the positional relationshipbetween the optical group MPL2 and the lens element 102 can beconstantly maintained, and it is therefore possible to ensure thatvibrations of the lens element 102 do not transmit to the optical groupMPL2.

At this time, the control apparatus CONT2 obtains the positioninformation of the lens element 102 with respect to the optical groupMPL2 in each of the X axial, Y axial, Z axial, θX, θY and AZ directionsby performing arithmetic processing based on the measurement results ofthe encoders 177, 178 provided in each of the six link parts 161. Inaddition, the control apparatus CONT2 controls the position of the lenselement 102 with respect to the optical group MPL2 in each of the Xaxial, Y axial, Z axial, θX, θY and θZ directions by expanding andcontracting each of the six link parts 161.

Furthermore, because vibrations produced when driving the first voicecoil motor 172 are absorbed by the action of the tubular member 167 as acounter mass, which is a vibration isolating mechanism built in the linkpart 161, it is possible to ensure that the vibrations are nottransmitted to the optical group MPL2 via the lens barrel base plate 108and the lens barrel PK2. Accordingly, it is possible to preventdegradation of the pattern image projected onto the substrate P2.

In addition, by preventing the transmission of the vibrations to theoptical group MPL2 and to the lens barrel PK2 that holds the opticalgroup MPL2, the measurement of the position information of the substratestage PST2 and the control of its position based on those measurementresults can be performed with good accuracy, even if the referencemirror (fixed mirror) 181 of the interferometer system for measuring theposition information of the substrate stage PST2 is affixed to the lensbarrel PK2.

In the present embodiment, when each link part 161 is expanded andcontracted, and the attitude of the lens element 102 held by the lenscell LS2 is controlled, only the first voice coil motor 172 is driven,and the second voice coil motor 173 is not driven, as discussed above.In other words, when controlling the attitude of the lens element 102,electric power for its control is supplied only to the first voice coilmotor 172, and hardly any (or no) electric power is supplied to thesecond voice coil motor 173. Furthermore, when moving the first voicecoil motor 172 for controlling the attitude of the lens element 102, forexample, toward the arrow J1 side in FIG. 11, then the tubular member167 moves toward the arrow J2 side. At this time, the second linkingmember 166 linked to the lens barrel base plate 108 does not move.Depending on the scanning exposure conditions, there is a possibilitythat the tubular member 167 will continue to move only in, for example,the arrow J2 direction. In that case, there is a possibility that thefirst linking member 164 will disconnect from the tubular member 167 ifthe relative position gap between the tubular member 167 and the firstand second linking members 164, 166 increases. Therefore, when therelative position between the tubular member 167 and the first andsecond linking members 164, 166 exceeds a permissible value, the controlapparatus CONT2 corrects the position of the tubular member 167 bydriving the second voice coil motor 173. Furthermore, the second voicecoil motor 173 may be driven with a timing other than the exposureoperation, such as, for example, during replacement of the substrate,and/or the time from after the exposure of the first shot region untilbefore the exposure of the next second shot region. Furthermore, whenthe attitude of the lens element 102 (the lens cell LS2) is controlledby the first voice coil motor 172 during exposure, the vacuum apparatus176 maintains the space 174 at a constant pressure.

In the present embodiment, by negatively pressurizing the space 174between the first linking member 164 and the second linking member 166,the relative position (distance) between the first linking member 164and second linking member 166 which are linked in anon-contact manner ismaintained, even if the first linking member 164 receives a force, dueto, for example, the weight of the lens cell LS2 and its own weight ofthe first linking member 164, in a direction away from the secondlinking member 166. Further, by continuing to supply electric power tothe voice coil motors 172, 173, it is also possible that they will besubject to the weight of the lens cell LS2 and its own weight of thefirst linking member 164; in that case, there is a possibility that theamount of electric power supplied to the voice coil motors willincrease, and it cause the generation of heat. Because the link parts161 are disposed in the vicinity of the image plane of the projectionoptical system PL2, there is a possibility that the generation of heatwill cause degradation of the pattern image projected onto the substrateP2.

Furthermore, because the weight of the lens cell LS2 and its own weightof the first linking member 164 are supported by applying a negativepressure to the space 174, the electric power supplied to the voice coilmotors may be just the electric power for controlling the attitude ofthe lens cell LS2 (the lens element 102). Accordingly, the amount ofelectric power supplied to the voice coil motors can be curbed, and theproblems associated with the generation of heat can be suppressed.

Furthermore, a temperature regulator may be provided for adjusting thetemperature of (for cooling) these voice coil motors 172, 173 in orderto suppress the impact on the pattern image due to the generation ofheat by the voice coil motors 172, 173.

By providing the space 174, the elastic action of the gas of that space174 can reduce the high frequency component of the vibrations thatattempt to transmit from the lens cell LS2 side to the lens barrel baseplate 108 side.

Furthermore, because the relatively low frequency component of thevibrations is reduced by the voice coil motors, the link parts 161 (thecoupling apparatus 160) can achieve the affect of eliminating thevibrations over a broad frequency band. Thus, by combining activevibration isolation (dynamic vibration isolation) using the voice coilmotors with passive vibration isolation (passive vibration isolation)using the elastic action of the gas of the space 174, it is possible toeffectively suppress the transmission to the optical group MPL2 of thevibrations that act upon the lens element 102.

Furthermore, instead of a constitution wherein the weight of the lenscell LS2 and its own weight of the first linking member 164 are receivedby the space 174 negatively pressurized, the first linking member 164and the second linking member 166 may be linked by, for example, aspring member.

Furthermore, in the present embodiment, the lens cell LS2 is constitutedso that it holds only one lens element 102, but may be constituted sothat it holds a plurality of lens elements (optical elements).

In addition, in the exposure apparatus of the second embodiment as well,the projection optical system PL2 is divided into two groups: theoptical element 102, and the projection optical system main body MPL2between the mask M2 and the optical element 102; however, it may bedivided into three or more groups.

Furthermore, in the abovementioned embodiment, the second linking member166 of the link part 161 is linked to the lens barrel base plate 108,but may be linked to another member, e.g., the column 103 (the lowerside step part 103B).

Furthermore, in the abovementioned embodiment, the attitude control (thecontrol of the active vibration isolation from the optical group MPL2)of the lens element 102 is accomplished by feedback control based on theresult of measuring the position of the lens element 102 by the encoders177, 178; however, in that case, there is the possibility of controldelays. Therefore, it is also possible to perform active vibrationisolation with feedforward control, wherein, physical quantities relatedto the behavior of the exposure apparatus EX2 and/or the liquid 101during scanning exposure are obtained prior to performing the exposure,and the attitude of the lens element 102 is controlled by driving thelink part 161 (voice coil motor 172) during the exposure based on thoseobtained physical quantities. Furthermore, it is also possible tocombine feedback control and feedforward control.

If performing feedforward control, then a test exposure is performedbeforehand and a plurality of physical quantities are obtained. Namely,an identification test is performed on the system of the exposureapparatus EX2, and the dynamic characteristics, including the physicalquantities of that system, are obtained. In the identification test, thesubstrate stage PST2 is scanned in a state wherein the immersion areaAR2 is formed between the lens element 102 and the substrate P2 usingthe liquid supply mechanism 110 and the liquid recovery mechanism 120,and the physical quantities are detected using the abovementionedencoders 177, 178 and/or the laser interferometer 182. Furthermore, thevoice coil motors 172, 173 are, of course, not driven during theidentification test. The detected physical quantities include: the timeduring the exposure sequence; the position, speed, and acceleration ofthe substrate P2; the position, speed, and acceleration of the lenselement 102; the relative position, the relative speed, and the relativeacceleration between the lens element 102 and the substrate P2; and thelike. The position, speed, and acceleration values are detected for allX axial, Y axial, Z axial, θX, θY and θZ directions (six degrees offreedom). Furthermore, the detected physical quantities include theamount (volume and mass), for example, of the liquid 1 to be supplied.The plurality of physical quantities detected by the identification testare stored in the control apparatus CONT2. Based on the detectedphysical quantities, the control apparatus CONT2 determines the controlquantities (electric power for control) for driving the voice coilmotors 172 (173), and performs the exposure while driving the voice coilmotor 172 based on those determined physical quantities so that itvibrationally isolates the optical group MPL2. Thus, the controlapparatus CONT2 can use the voice coil motor 172 to perform vibrationisolation in accordance with the dynamic characteristics (operation) ofthe exposure apparatus EX2 itself, and can maintain the positionalrelationship between the optical group MPL2 and the lens element 102 inthe desired state.

Incidentally, as discussed above, the control apparatus CONT2 cancontrol the attitude of the lens element 102 by expanding andcontracting each of the plurality of link parts 161. Therefore, byactively controlling the attitude of the lens element 102 with respectto the optical group MPL2 by expanding and contracting the link parts161, the control apparatus CONT2 can adjust the pattern image to beformed on the substrate P2 via the projection optical system PL2.Furthermore, by driving the lens element 102, at least one of the imageplane, the image position, and the distortion can be controlled. Byemploying the constitution wherein the pattern image is adjusted bydriving the lens element 102, a high speed response can be achievedcompared to the constitution wherein the heavy substrate stage PST2 isdriven, because the relatively lightweight lens element 102 is driven,for example, when aligning the image plane of the projection opticalsystem PL2 to the surface of the substrate P2. Of course, in that case,both the substrate stage PST2 and the lens element 102 may be driven.

The abovementioned embodiment is constituted to obtain the attitude ofthe lens element 102 based on the measurement results of the encoders177, 178 provided in each of the six link parts 161. In this case,because the control apparatus CONT2 obtains the attitude information ofthe lens element 102 by performing arithmetic processing based on themeasurement results of the encoders 177, 178 of the six link parts 161,errors in the position measurement (arithmetic errors) may arise due toerrors in the attachment and the installation of the link parts 161, andthe like. Therefore, as shown in FIG. 12, the position information ofthe lens element 102 with respect to the optical group MPL2 may bemeasured by a measuring apparatus 190 including a laser interferometersystem. The control apparatus CONT2 controls the attitude of the lenselement 102 by expanding and contracting each of the link parts 161based on the measurement result of that measuring apparatus 190. Becausethe position information of the lens element 102 with respect to theoptical group MPL2 can be directly derived by the laser interferometersystem without going through arithmetic processing, the positioninformation of the lens element 102 can be derived with good accuracy.

In FIG. 12, the measuring apparatus (laser interferometer system) 190includes a movable mirror 191 provided at a predetermined position onthe +X side of the lens cell LS2, a reference mirror (fixed mirror) 192provided at a predetermined position on the +X side of the lens barrelPK2, and a laser interferometer 193 provided at a position opposing themovable mirror 191 and the reference mirror 192. The laserinterferometer 193 irradiates the movable mirror 191 with a measuringbeam (measuring light), and irradiates the reference mirror 192 with areference beam (reference light). The reflected lights respectively fromthe movable mirror 191 and the reference minor 192 based on the radiatedmeasuring beam and the reference beam are received by the lightreceiving portion of the laser interferometer 193, the laserinterferometer 193 causes these lights to interfere, and measures theamount of change of the optical path length of the measuring beam usingthe optical path length of the reference beam as a reference, andconsequently measures the position (coordinate) of the movable minor 191using the reference minor 192 as a reference. Because the referenceminor 192 is provided on the lens barrel PK2 and the movable mirror 191is provided on the lens cell LS2, the laser interferometer 193 canmeasure the position in the X axial direction of the lens cell LS2 withrespect to the lens barrel PK2. Likewise, although not shown, a movableminor and a reference minor are also provided on the +Y side of the lenscell LS2 and the lens barrel PK2, a laser interferometer is provided ata position opposing thereto, and this laser interferometer can measurethe position in the Y axial direction of the lens cell LS2 with respectto the lens barrel PK2. In addition, the position in the θZ direction ofthe lens cell LS2 with respect to the lens barrel PK2 can be measuredby, for example, the laser interferometer 193 irradiating the movableminor 191 and the reference mirror 192 with at least two beams lined upin a row in the Y axial direction.

Furthermore, laser interferometers 194 (194A-194C) are respectivelyaffixed to the lens barrel PK2 at a plurality of mutually differingpredetermined locations (three locations) in the circumferentialdirection of the lens barrel PK2. However, FIG. 12 representativelydepicts just the one laser interferometer 194A of the three laserinterferometers 194A-194C. In addition, a movable minor 195 is affixedat a position opposing each of the laser interferometers 194 on theupper surface of the lens cell LS2, and each movable mirror 195 isirradiated by a measuring beam from each of the laser interferometers194 parallel to the Z axial direction. Furthermore, the reference minorcorresponding to each laser interferometer 194 is affixed to the lensbarrel PK2 or built in the laser interferometer 194, but is not depictedin FIG. 12. The laser interferometer 194 can measure the position in theZ axial direction of the lens cell LS2 with respect to the lens barrelPK2. In addition, the position in the θX, θY directions of the lens cellLS2 with respect to the lens barrel PK2 can be measured based on themeasurement result of each of the three laser interferometers 194.

The measurement result of each of the abovementioned laserinterferometers is outputted to the control apparatus CONT2. The controlapparatus CONT2 expands and contracts each of the plurality of linkparts 161 based on the measurement result of each of the abovementionedlaser interferometers, i.e., based on the position information of thelens cell LS2 with respect to the lens barrel PK2 in each of the Xaxial, Y axial, Z axial, θX, θY and θZ directions, thereby enablingcontrol of the position of the lens cell LS2 with respect to the lensbarrel PK2 in each of the X axial, Y axial, Z axial, θX, θY and θZdirections.

Furthermore, in the present embodiment, the measuring apparatus 190measures the positional relationship between the lens cell LS2 and thelens barrel PK2; however, because the lens cell LS2 holds the lenselement 102 and the lens barrel PK2 holds the optical group MPL2, themeasurement of the positional relationship between the lens cell LS2 andthe lens barrel PK2 and the measurement of the positional relationshipbetween the lens element 102 and the optical group MPL2 aresubstantially equivalent. Accordingly, the control apparatus CONT2 canobtain the positional relationship between the lens element 102 and theoptical group MPL2 based on the measurement result of the measuringapparatus 190.

The laser interferometer in the present embodiment is a so-called doublepass interferometer.

FIG. 13 is a schematic block diagram of the interferometer 193.Furthermore, the other interferometers 194, 182 and the like also have aconstitution equivalent to the interferometer depicted in FIG. 13. Theinterferometer 193 includes a light source 220 that radiates a lightbeam; a polarizing beam splitter 224 that divides the light beam that isirradiated from the light source 220 and enters via a reflecting minor223 into a measuring beam 191A and a reference beam 192A; quarter-waveplates 225 (225A, 225B) disposed between the polarizing beam splitter224 and the movable mirror 191 and through which passes the measuringbeam 191A from the polarizing beam splitter 224; quarter-wave plates 226(226A, 226B) disposed between the polarizing beam splitter 224 and thereference minor 192 and through which passes the reference beam 192Afrom the polarizing beam splitter 224 via a reflecting minor 227; acorner cube 228 to which the measuring beam 191A reflected by themovable mirror 191 and the reference beam 192A reflected by thereference mirror 192 enters via the polarizing beam splitter 224; and alight receiving portion 230 that receives the synthesized light(interference light) of the reflected light of the measuring beam 191Aand the reflected light of the reference beam 192A synthesized by thepolarizing beam splitter 224.

The light beam that enters the polarizing beam splitter 224 from thelight source 220 is divided into the measuring beam 191A and thereference beam 192A. The measuring beam 191A passes through thequarter-wave plate 225A, and then irradiates the movable minor 191. Bypassing through the quarter-wave plate 225A, the linearly polarizedmeasuring beam 191A is converted to circularly polarized light, and thenirradiates the movable minor 191. The reflected light of the measuringbeam 191A that irradiated the movable mirror 191 once again passesthrough the quarter-wave plate 225A, then enters the polarizing beamsplitter 224 and is sent to the corner cube 228. The measuring beam 191Afrom the corner cube 228 once again enters the polarizing beam splitter224, passes through the quarter-wave plate 225B, and then irradiates themovable mirror 191. That reflected light once again passes through thequarter-wave plate 225B, and enters the polarizing beam splitter 224.The reference beam 192A emitted from the polarizing beam splitter 224passes through the quarter-wave plate 226A via the reflecting minor 227,and then irradiates the reference minor 192. The reference beam 192Airradiates the reference minor 192 with circularly polarized light. Thereflected light once again passes through the quarter-wave plate 226A,then enters the polarizing beam splitter 224 and is sent to the cornercube 228. The reference beam 192A from the corner cube 228 once againenters the polarizing beam splitter 224, passes through the quarter-waveplate 226B, and then irradiates the reference minor 192. The reflectedlight once again passes through the quarter-wave plate 226B, and thenenters the polarizing beam splitter 224. The measuring beam 191A thatpassed through the quarter-wave plate 225B and the reference beam 192Athat passed through the quarter-wave plate 226B are synthesized by thepolarizing beam splitter 224, and then received by the light receivingportion 230. Thus, the interferometer 193 of the present embodimentincludes a so-called double pass interferometer that twice irradiates amovable mirror (reference minor) with a measuring beam (reference beam);even if the movable minor 191 is, for example, inclined, theinterferometer 193 has a characteristic in that there is no change inthe travel direction of the reflected light of the measuring beam fromthat movable minor 191.

FIG. 14 is a schematic view of the double pass interferometer.

FIG. 14 depicts only the measuring beam 191A that irradiates the movablemirror 191, and omits the quarter-waveplates, and the like.

In FIG. 14, the light beam emitted from the light source 220 enters thepolarizing beam splitter 224 via the reflecting mirror 223. The lengthmeasuring beam 191A is reflected by the reflecting surface of thepolarizing beam splitter 224, and then irradiates the reflecting surfaceof the movable mirror 191; after the reflected light twice irradiatesthe reflecting surface of the movable mirror 191 via the polarizing beamsplitter 224 and the corner cube 228, it is received by the lightreceiving portion 230. At that time, if the reflecting surface of themovable mirror 191 is not inclined (if the angle with the Y axis is 0°,then the measuring beam 191A travels as depicted by the broken line inFIG. 14, and the exit light beam emitted from the polarizing beamsplitter 224 towards the light receiving portion 230 becomes parallel tothe incident light beam that enters the polarizing beam splitter 224. Onthe other hand, if the reflecting surface of the movable mirror 191 isinclined at an angle θ, then the measuring beam travels as depicted bythe chain line 191A′ in FIG. 14. In this case as well, the exit lightbeam from the polarizing beam splitter 224 becomes parallel to theincident light beam. In other words, the travel directions of each ofthe exit light beams are the same regardless of whether the reflectingsurface of the movable mirror 191 is inclined. Accordingly, if theconstitution is such that the measuring beam 191A irradiates the movableminor 191 one time, as in the schematic view depicted in FIG. 15, then,if the movable minor 191 is inclined, the travel direction of thatreflected light with respect to the uninclined state changes, causing aproblem wherein the light is not received by the light receiving portion230. However, as explained referencing FIG. 14, even if the movableminor 191 is, for example, inclined, a double pass interferometer canreceive that reflected light by the light receiving portion 230.

Furthermore, in the present embodiment explained referencing FIG. 12,the measuring apparatus 190 including the laser interferometers 193, 194measures the positional relationship between the lens barrel PK2 and thelens cell LS2; however, a reflecting member having a reflecting surfacecapable of reflecting the radiated measuring beam may be provided at apredetermined position of the lens element 102, and the laserinterferometer may irradiate that reflecting surface with the measuringbeam. For example, as depicted in FIG. 16, a mirror member having areflecting surface may be affixed at a position on the lens element 102where the measuring beam from the laser interferometer 193 will beirradiated, a vacuum metallized film may be provided at a position wherethe measuring beam from the laser interferometer 194 will be irradiated,and that film surface may be a reflecting surface. For example, if it isconstituted so that a spring mechanism (flexure) is interposed betweenthe lens cell LS2 and the lens element 102, and if the lens cell LS2 andthe lens element 102 are temporarily mispositioned, then if an attemptis made to control the attitude of the lens element 102 in order toadjust the pattern image based on the position measurement result of thelens cell LS2, as in the embodiment explained referencing FIG. 12, thenthere is a possibility that the pattern image cannot be controlled toachieve the desired state; however, the position information of the lenselement 102 can be accurately derived by forming the reflecting surfaceon the lens element 102 itself and measuring the position of the lenselement 102 using that reflecting surface, as depicted in FIG. 16.

Furthermore, in the present embodiment discussed above, aninterferometer system is used as the measuring apparatus 190, but ameasuring apparatus that employs another system may be used. Forexample, instead of the interferometer system discussed above, it ispossible to use a measuring apparatus that optically measures theposition information of a measurement mark formed on the lens cell LS2.

In addition, because the coupling apparatus 160 can move the lenselement 102, it is possible to form the immersion area AR2 between thelens element 102 and the substrate P2 by sufficiently enlarging thedistance between the substrate P2 and the lens element 102 bypre-raising the lens element 102 using the coupling apparatus 160,disposing the liquid on the substrate P2, and subsequently driving thecoupling apparatus 160 to lower the lens element 102 and bring the lenselement 102 proximate to the substrate P2, when, for example, fillingthe liquid 101 between the lens element 102 and the substrate P2. Inthis case, when lowering the lens element 102, by bringing the lenselement 102 proximate (lowering) to the substrate P2 from the inclineddirection, it is possible to remove any bubbles that may exist, forexample, in the liquid 101. In addition, when supplying the liquid 101onto the substrate P2 prior to exposure, it is possible to dispose theliquid 101 onto the substrate P2 using, for example, a liquid supplyapparatus provided at a position separate from the liquid supplymechanism 110, without using the liquid supply mechanism 110.

The above embodiments are not particularly limited to the nozzleconfigurations discussed above, e.g., the liquid 101 may be supplied andrecovered by two pairs of nozzles on the long sides of the projectionarea AR1. Furthermore, in this case, the supply nozzles and the recoverynozzles may be disposed so that they are arrayed vertically in order toenable the supply and recovery of the liquid 101 from either the +Xdirection or the −X direction.

In addition, in the embodiments discussed above, the two object couplingapparatus used in the parallel link mechanism is used to support thelens cell LS2, but the embodiments are not limited thereto, and thecoupling apparatus may be used, for example, to support the substrateholder PH2.

As discussed above, the liquids 50, 101 in the above embodiments includepure water. Pure water is advantageous because it can be easily obtainedin large quantities at a semiconductor fabrication plant, and the like,and because pure water has no adverse impact on the optical elements(lenses), the photoresist on the substrates P, P2, and the like. Inaddition, because pure water has no adverse impact on the environmentand has an extremely low impurity content, it can also be expected tohave the effect of cleaning the surfaces of the substrates P, P2, andthe surfaces of the optical element provided on the tip surfaces of theprojection optical systems PL, PL2.

Further, because the refractive index n of pure water (water) for theexposure lights EL, EL2 having a wavelength of approximately 193 nm issubstantially 1.44, the use of ArF excimer laser light (193 nmwavelength) as the light sources of the exposure lights EL, EL2 wouldshorten the wavelength on the substrates P, P2 to 1/n, i.e.,approximately 134 nm, thereby obtaining a high resolution. Furthermore,because the depth of focus will increase approximately n times, i.e.,approximately 1.44 times, that of in air, the numerical aperture of theprojection optical systems PL, PL2 can be further increased if it ispreferable to ensure a depth of focus approximately the same as thatwhen used in air, and the resolution is also improved from thisstandpoint.

In the present embodiment, the lenses 60, 102 are affixed at the tip ofthe projection optical systems PL, PL2. As an optical element that isaffixed at the tip of the projection optical systems PL, PL2, it may bean optical plate used to adjust the optical characteristics, e.g.,aberrations (spherical aberration, coma aberration, and the like), ofthe projection optical systems PL, PL2. Alternatively, it may be a planeparallel plate capable of transmitting the exposure light ELtherethrough.

Furthermore, although the liquids 50, 101 in the above embodiments arewater, they may be a liquid other than water; for example, if the lightsources of the exposure lights EL, EL2 are F₂ lasers, then the F₂ laserlight will not transmit through water, so it would be acceptable to useas the liquids 50, 101 a fluorine based liquid, such as perfluorinatedpolyether (PFPE) or fluorine based oil, that is capable of transmittingF₂ laser light. In addition, it is also possible to use one as theliquids 50, 101 (e.g., cedar oil) that is transparent to the exposurelights EL, EL2, has the highest possible refractive index, and is stablewith respect to the projection optical systems PL, PL2 and thephotoresist coated on the surfaces of the substrates P, P2.

Furthermore, the substrates P, P2 in each of the abovementionedembodiments is not limited to a semiconductor wafer for fabricatingsemiconductor devices, and is also applicable to a glass substrate for adisplay device, a ceramic wafer for a thin film magnetic head, or a maskor original plate of a reticle (synthetic quartz, silicon wafer) used byan exposure apparatus, and the like.

In addition, in the embodiments discussed above, an exposure apparatusis used that locally fills liquid between the projection optical systemsPL, PL2 and the substrates P, P2, but the present invention is alsoapplicable to a liquid immersion exposure apparatus that moves a stage,which holds the substrate to be exposed, in a liquid bath, as disclosedin Japanese Unexamined Patent Application, First Publication No.H06-124873, as well as to a liquid immersion exposure apparatus thatforms a liquid bath having a predetermined depth on the stage, and holdsthe substrate therein, as disclosed in Japanese Unexamined PatentApplication, First Publication No. H10-303114.

In addition to a step-and-scan system scanning type exposure apparatus(scanning stepper) that scans and exposes the patterns of the masks M,M2 while synchronously moving the masks M, M2 and the substrates P, P2,a step-and-repeat system projection exposure apparatus (stepper) thatexposes the full patterns of the masks M, M2 with the masks M, M2 andthe substrates P, P2 in a stationary state and sequentially steps thesubstrates P1, P2 is also applicable to the exposure apparatuses EX,EX2. In addition, the present invention is also applicable to astep-and-stitch system exposure apparatus that partially andsuperimposingly transfers at least two patterns onto the substrates P,P2.

In addition, the present invention is also applicable to twin stage typeexposure apparatuses that include two stages where substrates to beprocessed, e.g., wafers, are mounted separately, and that can move thosesubstrates independently in the XY directions. The structure and theexposure operation of a twin stage type exposure apparatus is disclosedin, for example, Japanese Unexamined Patent Application, FirstPublication No. H10-163099 and Japanese Unexamined Patent Application,First Publication No. H10-214783 (corresponding U.S. Pat. Nos.6,341,007; 6,400,441; 6,549,269; and 6,590,634); Published Japanesetranslation No. 2000-505958 of PCT International Publication(corresponding U.S. Pat. No. 5,969,441); or U.S. Pat. No. 6,208,407; andthe contents thereof are hereby incorporated by reference in theirentireties to the extent permitted by the laws and regulations of thestates designated or elected by the present international patentapplication.

The types of exposure apparatuses EX, EX2 are not limited tosemiconductor device fabrication exposure apparatuses that expose thepattern of a semiconductor device on the substrates P, P2, but is alsowidely applicable to exposure apparatuses for fabricating liquid crystaldevices or displays, exposure apparatuses for fabricating thin filmmagnetic heads, imaging devices (CCD), reticles and masks, and the like.

If a linear motor is used in the substrate stage PST and/or the maskstage MST, then either an air levitation type that uses an air bearingor a magnetic levitation type that uses Lorentz's force or reactanceforce may be used. In addition, each of the stages PST, MST may be atype that moves along a guide, or may be a guideless type not providedwith a guide. An example of using a linear motor in a stage is disclosedin U.S. Pat. Nos. 5,623,853 and 5,528,118, and the contents thereof arehereby incorporated by reference in their entireties to the extentpermitted by the laws and regulations of the states designated orelected by the present international patent application.

For the drive mechanism of each of the stages PST, PST2, MST, MST2, aplanar motor may be used that disposes a magnet unit, wherein magnetsare arranged two dimensionally, opposing an armature unit, wherein coilsare arranged two dimensionally, and drives each of the stages PST, PST2,MST, MST2 by electromagnetic force. In this case, any one among themagnet unit and the armature unit is connected to the stages PST, PST2,MST, MST2, and the other one of the magnet unit and the armature unitshould be provided on the moving surface side of the stages PST, PST2,MST, MST2.

The reaction force generated by the movement of the substrate stage PSTmay be mechanically discharged to the floor (ground) using a framemember so that it is not transmitted to the projection optical systemPL. A method of handling this reaction force is disclosed in detail in,for example, U.S. Pat. No. 5,528,118 (Japanese Unexamined PatentApplication, First Publication No. H08-166475), and the contents thereofare hereby incorporated by reference in their entireties to the extentpermitted by the laws and regulations of the states designated orelected by the present international patent application.

The reaction force generated by the movement of the mask stage MST maybe mechanically discharged to the floor (ground) using a frame member sothat it is not transmitted to the projection optical system PL. A methodof handling this reaction force is disclosed in detail in, for example,U.S. Pat. No. 5,874,820 (Japanese Unexamined Patent Application, FirstPublication No. H08-330224), and the contents thereof are herebyincorporated by reference in their entireties to the extent permitted bythe laws and regulations of the states designated or elected by thepresent international patent application.

The exposure apparatuses EX, EX2 of the embodiments are manufactured byassembling various subsystems, including each constituent elementrecited in the claims of the present application, so that apredetermined mechanical accuracy, electrical accuracy, and opticalaccuracy are maintained. To ensure these various accuracies, adjustmentsare performed before and after this assembly, including an adjustment toachieve optical accuracy for the various optical systems, an adjustmentto achieve mechanical accuracy for the various mechanical systems, andan adjustment to achieve electrical accuracy for the various electricalsystems.

The assembly process, from the various subsystems to the exposureapparatus includes the mutual mechanical connection of the varioussubsystems, the wiring and connection of electrical circuits, the pipingand connection of the atmospheric pressure circuit, and the like.Naturally, before the process of assembling from these varioussubsystems to the exposure apparatus, there are processes for assemblingeach of the individual subsystems. When the assembly process rangingfrom various subsystems to the exposure apparatus has been completed, acomprehensive adjustment is performed to ensure the various accuraciesof the exposure apparatus as a whole. Furthermore, it is preferable tomanufacture the exposure apparatus in a clean room where thetemperature, the cleanliness level, and the like, are controlled.

As shown in FIG. 17, a micro-device, such as a semiconductor device, ismanufactured by: a step 201 that designs the functions and performanceof the micro-device; a step 202 that fabricates a mask (reticle) basedon this design step; a step 203 that fabricates a substrate, which isthe base material of the device; a substrate processing step 204 whereinthe exposure apparatus EX of the embodiments discussed above exposes apattern of the mask onto the substrate; a device assembling step 205(including a dicing process, a bonding process, and a packagingprocess); a scanning step 206; and the like.

The present invention is an exposure apparatus that exposes a substrateby filling a liquid between a projection optical system and a substrateand then projecting a pattern image onto the substrate via theprojection optical system and the liquid, wherein the projection opticalsystem includes a first group having an optical member that contacts theliquid, and a second group different from the first group; and, becausethat first group and second group are supported vibrationally isolated,degradation of the pattern image can be suppressed and a high precisiondevice can be manufactured, even in the state wherein the liquid isfilled between the projection optical system and the substrate.

1. A lithographic projection apparatus comprising: an illuminationsystem arranged to condition a radiation beam; a support structureconfigured to hold a patterning device, the patterning device beingcapable of imparting the radiation beam with a pattern; a substratetable configured to hold a substrate; a projection system arranged toproject the patterned radiation beam onto a target portion of thesubstrate, the projection system comprising a first part and a secondpart that are two separate physical parts that are substantiallyisolated from each other such that vibrations in the second part aresubstantially prevented from being transferred to the first part,wherein each part comprises an optical element of the projection systemand the first and second parts are not attached to and movable with thesubstrate; and a liquid supply system configured to at least partly filla space between the projection system and the substrate, with a liquid.2. The lithographic apparatus according to claim 1, wherein the parts ofthe projection system are separated at a location between two lenselements having a large curvature radius, between two lens elementswhere the patterned beam is collimated, or both.
 3. The lithographicapparatus according to claim 1, wherein the projection system is atelecentric lens system and the parts are separated at a pupil plane ofthe lens system.
 4. The lithographic apparatus according to claim 1,further comprising: a sensor configured to establish a position betweena first optical element in the first part of the projection system and asecond optical element in the second part of the projection system; anactuator configured to vary the position between the first and secondoptical elements; and a controller configured to control the actuator onthe basis of output from the sensor to maintain a predetermined positionbetween the first and second optical elements.
 5. The lithographicapparatus according to claim 4, wherein the position is a distance inthe direction substantially parallel to the direction of the opticalaxis of the projection system.
 6. The lithographic apparatus accordingto claim 1, further comprising: an actuator configured to vary theposition between the first and second parts; and a controller configuredto control the actuator to maintain a predetermined relative positioningbetween the first and second parts.
 7. The lithographic apparatusaccording to claim 1, wherein the second part of the projection systemis attached to the liquid supply system.
 8. The lithographic apparatusaccording to claim 1, wherein the liquid supply system comprises a sealmember configured to seal liquid in at least part of the space betweenthe projection system and the substrate.
 9. The lithographic apparatusaccording to claim 8, wherein the seal member further comprises acontactless seal configured to seal liquid in the space.
 10. Thelithographic apparatus according to claim 1, wherein the second part isat least partly supported by a resilient member connected between thesecond part and a base frame.
 11. The lithographic apparatus accordingto claim 10, wherein the base frame is decoupled from a frame to whichthe first part is attached.
 12. A device manufacturing method,comprising: providing a liquid to a space between a substrate on asubstrate table of a lithographic apparatus and a first part of aprojection system of the lithographic apparatus, a second part of theprojection system being substantially isolated from the first part suchthat vibrations in the second part are substantially prevented frombeing transferred to the first part and the first and second parts arenot attached to and movable with the substrate; and projecting apatterned beam of radiation, using the first and second parts of theprojection system, through the liquid onto a target portion of asubstrate.
 13. The method according to claim 12, further comprising:establishing a position between a first optical element in the firstpart of the projection system and a second optical element in the secondpart of the projection system; and adjusting the position of the firstoptical element, the second optical element, or both such that theestablished position is maintained at a predetermined position.
 14. Themethod according to claim 13, wherein the position is a distance in thedirection substantially parallel to the direction of the optical axis ofthe projection system.
 15. The method according to claim 12, furthercomprising adjusting the relative positioning of the first and secondparts of the projection system to maintain a predetermined relativepositioning between them.
 16. The method according to claim 12, whereinthe parts of the projection system are separated at a location betweentwo lens elements having a large curvature radius, between two lenselements where the patterned beam is collimated, or both.
 17. The methodaccording to claim 12, wherein the projection system is a telecentriclens system and the parts are separated at a pupil plane of the lenssystem.
 18. The method according to claim 12, comprising sealing theliquid in at least part of the space between the projection system andthe substrate using a seal member.
 19. The method according to claim 18,wherein sealing the liquid comprises sealing the liquid in the spaceusing a contactless seal.
 20. The method according to claim 12,comprising at least partly supporting the second part using a resilientmember connected between the second part and a base frame of thelithographic apparatus.
 21. The method according to claim 20, whereinthe base frame is decoupled from a frame to which the first part isattached.